Spatial coherent X-ray source of surface-transmitting array structure

Abstract

The invention provides a spatial coherent X-ray source, and the X-ray source comprises a cathode, an electron beam gathering device and a transmitting anode target. The cathode comprises a surface-transmitting type electron emitter, and the surface-transmitting type electron emitter, the electron beam gathering device and the transmitting anode target are sequentially disposed on a coaxial opticalpath. The surface-transmitting type electron emitter has a transmitting plane which is perpendicular to the optical axis and used for transmitting a first electron beam. The electron beam gathering device is used for receiving and gathering the first electron beam emitted by the transmitting plane to obtain a second electron beam, and transmitting the second electron beam to the transmitting anode target to bombard the transmitting anode target. The transmitting anode target is opposite to the cathode, and is used for generating X-rays under the bombardment of the second electron beam, and enabling the X-rays to pass through the transmitting anode target. According to the invention, the X-ray source can meet the requirements of the high throughput, large view field and high-quality imageobtaining of the X-ray source in an X-ray interference imaging system.

Description

technical field [0001] The invention relates to the field of X-ray interference imaging, in particular to a space-coherent X-ray source with a surface emission transmission array structure. Background technique [0002] X-ray grating interference imaging technology is a hotspot in the current research of X-ray phase contrast imaging technology. X-ray grating interference imaging technology was proposed by German scientist Dr. F.Pfeiffer in 2006. It uses source grating plus ordinary X-ray tube to obtain a coherent X-ray source, which makes X-ray phase contrast imaging research get rid of the need for synchrotron radiation. The dependence of the light source makes it possible for the X-ray grating phase contrast imaging technology to be realized in ordinary laboratories and hospitals. [0003] However, the method of utilizing the source grating proposed by F.Pfeiffer makes the effective field of view of the X-ray imaging system limited by the viewing angle of the X-ray tube b...

AI Technical Summary

Problems solved by technology

Due to the limitation of the exit window, most of the X-rays reflected from the surface of the anode target are intercepted, and only a small part is radiated from the window. The radiated X-rays have a small divergence angle, resulting in a limited imaging field of view; The array X-ray source is extended and distributed in the direction of the optical axis, so that the distance from each line emitter in the array X-ray source to the detection surface is not equal, which is not conducive to the extraction of imaging information by the plane detector, and also limits the system's Field of view

Especially in ordinary laboratories and hospitals, large field of view imaging is usually required. Since the imaging field of view of this array X-ray source is limited, it is difficult to apply it in large field of view X-ray differential imaging

[0008] Second, in terms of light extraction characteristics, the above-mentioned anode light extraction efficiency is low

In order to facilitate heat dissipation, reflective targets are usually made thicker and made on very thick copper electrodes. Most of the X-rays generated by electronic targeting are absorbed by the target and heat-dissipating electrodes, and only the X-rays generated by a very thin layer on the surface can Radiate from the target surface; and due to the limitation of the reflective structure, only the X-rays radiated at a certain angle will radiate from the window, and the X-rays emitted at most angles will be intercepted and cannot be effectively used, which is serious. Limits the utilization efficiency of X-rays

[0009] Third, due to the use of the spiral filament structure of the traditional X-ray tube, electrons are easily suppressed by space charges and filament field distribution during emission, which affects their emission efficiency; and due to the spiral structure of the filament, the emitted electron bundles diverge Larger angle affects the control of the subsequent focusing electric field on the morphology of the electron focal spot, thereby affecting the uniformity of electron distribution on the focal plane

[0010] In summary, the existing reflective X-ray sources do not meet the requirements of imaging systems for high-throughput, large field of view, and high-quality images of X-ray sources.

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